Hi BitLex,
After testing the website for a few days, I still really think there is a great opportunity for improvement on the conversion rate side, here.

I think your "New Unique Visitor" to "Registered User" must be pretty high (after all, who doesn't want to earn bitcoins?), but I am afraid many users don't even know what to do once they are registered, therefore implying a relatively low "Registered User" to "Paying Member" conversion rate...

Do you have the stats of these conversion rates? Would you mind sharing them with us? The cool thing is that I am sure there's a lot we can do to improve this!

Just an example that just came to my mind, in order to improve the Registered User to Paying Member conversion rate: what about sending a short and nice e-mail to those who haven't payed their bitcoin yet, explaining them how they can send the bitcoin?
Yeah, I admit that doing online marketing is my job and I find it pretty exciting!

Can't wait to help you, if you are still enthusiastic about this project!